using System;
using System.Collections.Generic;
using System.Linq;
using StardewModdingAPI.Mods.ConsoleCommands.Framework.Commands;

namespace StardewModdingAPI.Mods.ConsoleCommands;

/// <summary>The main entry point for the mod.</summary>
public class ModEntry : Mod
{
    /*********
    ** Fields
    *********/
    /// <summary>The commands to handle.</summary>
    private IConsoleCommand[] Commands = null!;

    /// <summary>The commands which may need to handle update ticks.</summary>
    private IConsoleCommand[] UpdateHandlers = null!;


    /*********
    ** Public methods
    *********/
    /// <summary>The mod entry point, called after the mod is first loaded.</summary>
    /// <param name="helper">Provides simplified APIs for writing mods.</param>
    public override void Entry(IModHelper helper)
    {
        // register commands
        this.Commands = this.ScanForCommands().ToArray();
        foreach (IConsoleCommand command in this.Commands)
            helper.ConsoleCommands.Add(command.Name, command.Description, (name, args) => this.HandleCommand(command, name, args));

        // cache commands
        this.UpdateHandlers = this.Commands.Where(p => p.MayNeedUpdate).ToArray();

        // hook events
        helper.Events.GameLoop.UpdateTicked += this.OnUpdateTicked;
    }


    /*********
    ** Private methods
    *********/
    /// <summary>The method invoked when the game updates its state.</summary>
    /// <param name="sender">The event sender.</param>
    /// <param name="e">The event arguments.</param>
    private void OnUpdateTicked(object? sender, EventArgs e)
    {
        foreach (IConsoleCommand command in this.UpdateHandlers)
            command.OnUpdated(this.Monitor);
    }

    /// <summary>Handle a console command.</summary>
    /// <param name="command">The command to invoke.</param>
    /// <param name="commandName">The command name specified by the user.</param>
    /// <param name="args">The command arguments.</param>
    private void HandleCommand(IConsoleCommand command, string commandName, string[] args)
    {
        ArgumentParser argParser = new(commandName, args, this.Monitor);
        command.Handle(this.Monitor, commandName, argParser);
    }

    /// <summary>Find all commands in the assembly.</summary>
    private IEnumerable<IConsoleCommand> ScanForCommands()
    {
        return (
            from type in this.GetType().Assembly.GetTypes()
            where !type.IsAbstract && typeof(IConsoleCommand).IsAssignableFrom(type)
            select (IConsoleCommand)Activator.CreateInstance(type)!
        );
    }
}
